In a cloud platform, such as IaaS (Infrastructure as a Service), a plurality of virtual datacenters for users, referred to below as (vDCs), reside together, that is, the virtual datacenters are run as they share physical resources on the cloud platform, and a diversity of virtual systems, such as Web servers or systems for distribution of animated pictures, are run on the vDCs.
The use states of these virtual systems are changing with time. Hence, there is known an autonomous control technique which causes the quantities of allocation of server resources, such as virtual CPUs (Central Processing Units) or memories, to be changed in real-time in keeping with the changing use states.
Patent Literature 1 shows a system for brokering resources, in which priority levels for services allocated to respective nodes of resources are associatively set for the nodes of resources, and in which the priority levels set for the respective nodes of resources are updated to higher levels with lapse of processing time of the respective services rendered by the nodes. If there are no vacant nodes of resources to be allocated to a new service, the service(s) allocated to one of a first node of resources and a second node of resources, the services are already allocated to, is changed over to the new service, providing that the node of resources, for which the service has thus been changed over to the new service, has an as-updated priority level lower than the other node of resources.
Patent Literature 2 shows a communication service control system in which the transmission priority level and the call loss ratio are synthesized together to differentiate the service level to implement multiple classes of the quality levels of communication services. It is stated in Patent Literature 2 that the communication service control system includes a transmission control means, controlling the information transmission over a network, based on the transmission priority level, a management means for resources and an admission control means. The management means for resources causes a threshold value of the quantity of resources to be stored in a memory in which the threshold value is correlated with the values of preset multiple admission priority levels of requests for exploiting the communication services. In more detail, the threshold value stored in the memory becomes greater the higher the values of the preset multiple admission priority levels. If there is made a request(s) for exploiting the communication services, the admission control means sums the quantity of use of the resources requested to the current quantity of use of the resources by links used for the communication services of interest. The admission control means then reads out from the memory the threshold value of the quantity of resources corresponding to the admission priority level of the request(s) for use of the resources in question, and compares the so read out threshold value to the sum of the quantities of use of the resources. If the sum of the quantities of use of the resources is not greater than the threshold value, the admission control means admits the request(s) for use. If otherwise, the admission control means refuses the request(s) for use. It is stated that, with the disclosed communication service control system, the standard or reference of the quantity of residual resources that may be admitted is varied for communication services of the same transmission priority level in dependence upon the admission priority level to differentiate the communication quality levels of the communication services having the same transmission priority level. It is also stated that, by so doing, communication services can be provided at a plurality of communication quality levels resulting from combination of the transmission control which is based on the transmission priority level with the admission control which is based on the admission priority level.
Patent Literature 3 shows a distributed work flow simulation system which takes into consideration the influence of resource sharing in a distributed work flow system that manages the flow of business processing by a plurality of work flow execution units.
Non-Patent literatures 1, 2 introduce a technique, termed OpenFlow, enabling dynamic control of network resources.